Most rookies admit the adjustment from college to NFL is fast. For rookie linebacker Mason Foster, his learning curve is on speed dial.

Foster learned another lesson on Thursday — that the NFL is serious about hits to the head or to defenseless receivers. Even questionable ones.

Foster was flagged 15 yards after a bang-bang play in which he nailed New England receiver Chad Ochocinco. Ochocinco popped right up after the play but the third-round pick Foster was nailed with a penalty. He could be fined this week after the NFL looks at the play.

“I was running in Cover-2 — middle coverage, stay in between the hashes — looked over and didn’t see any threat this way, so I flipped back and just broke on the ball and ran right into it,” Foster said. “It was a good play but they threw a flag and it kind of put a dark cloud over it. I know better. That’s a learning experience so I know how to change the way you hit or whatever.”

Ochocinco thought it was a good play and reached out to Foster on Twitter, telling the rookie he thought it was a good hit and if he was fined, he would reimburse him.

Bucs coach Raheem Morris expects more close plays to be flagged this year.

“Like I said after the game, and I know coaches hate this but (officials are) going to err on the side of caution,” Morris said. “Whether it’s a mistake or not, we’ll have to find out when everyone has a chance to review the tape. Really, it might have been a mistake, which happens, and that’s OK.”